Imprinted micro-louver structure

ABSTRACT

A micro-louver structure includes a cured layer on a surface. A plurality of micro-channels forms a pattern in the cured layer. The micro-channels have a greater depth than width and are spaced apart by a separation distance greater than the width. A cured light-absorbing material is located in the micro-channels.

CROSS REFERENCE TO RELATED APPLICATION

Reference is made to commonly-assigned U.S. patent application Ser. No.______ filed concurrently herewith, entitled “Imprinted Micro-LouverStructure Method” by Ronald S. Cok, the disclosure of which isincorporated herein.

FIELD OF THE INVENTION

The present invention relates to micro-louver structures.

BACKGROUND OF THE INVENTION

Micro-louver structures are widely used for privacy screens to inhibitdisplay viewing at large angles from an angle orthogonal to the display.Micro-louver structures are also useful for rejecting specularillumination of a surface at large angles from an angle orthogonal tothe surface. For example, U.S. Pat. No. 5,543,870 describes arear-projection screen with two crossed films of micro-louver lightcontrol material to provide a high degree of blocking of high-intensitylight, such as sunlight that can impinge upon the front of the screen.U.S. Patent Application Publication 20090242142 describes a verticalmicro-louver structure with variable angles or depths. U.S. PatentApplication Publication 20080144179 describes a micro-louver sheetincluding a diffuser layer in a central portion of the sheet to vary thelight distribution of the sheet.

Referring to the perspective of FIG. 15, prior-art micro-louverstructures are typically composed of alternating portions of alight-absorbing material 84 and a transparent material 86 arranged in amicro-louver sheet 12. The light-absorbing material 84 extends a depth Din a z dimension Z orthogonal to a micro-louver sheet surface 11 of themicro-louver sheet 12 and in a y dimension Y a length L parallel to themicro-louver sheet surface 11 to form parallel micro-louvers 23extending through and along the micro-louver sheet 12 leavingtransparent portions of the micro-louver sheet 12 through which light 50can pass. The width W of the micro-louvers 23 in an x dimension Xparallel to the micro-louver sheet surface 11 and orthogonal to the Ydimension is relatively small compared to the length L of themicro-louvers 23 in the X dimension. It is also desirable that the widthW of the micro-louvers 23 is relatively small compared to the depth D ora separation distance S between the micro-louvers 23 in the X dimension.In general, it is useful to make the width W of the micro-louvers 23 assmall as possible to increase the transparency of the micro-louver sheet12 in the Z dimension.

A cross-section A of the micro-louver sheet 12 in a plane parallel tothe micro-louver sheet surface 11 has only a small proportion of thelight-absorbing material 84 compared to the transparent material 86.Hence, most of the light 54 passing through the micro-louver sheet 12 atan angle orthogonal to the surface of the micro-louver sheet 12 indimension Z or light 50 emitted parallel to an extensive surface 28 ofthe light-absorbing material 84 in dimensions Y and Z will pass throughthe micro-louver sheet 12. In contrast, blocked light 52 passing throughthe micro-louver sheet 12 at a larger angle to the orthogonal indimension X or that is not parallel to the extensive surface 28 of thelight-absorbing material 84 is absorbed by the light-absorbing material84. Thus, the blocked light 52 passing through the micro-louver sheet 12at large angles from a display 40 located adjacent to the micro-louversheet 12 cannot be seen in the X dimension, while orthogonal emittedlight 54 passing through the micro-louver sheet 12 orthogonally to themicro-louver sheet 12 in the Z dimension or parallel to the extensivesurface 28 of a light-absorbing material 24 in the Y or Z dimensions canbe seen. The micro-louver sheet 12, therefore, forms a privacy screen inthe X dimension but not in the Y dimension.

The angle at which the blocked light 52 is absorbed in the X dimensionand the transparency of micro-louver sheet 12 in the Z dimension dependupon the depth D and the separation distance S of the micro-louvers 23.In prior-art systems, the micro-louver sheet 12 is laminated to acomponent of a display 40, for example a display cover 42 through whichlight is emitted by the display 40. Two privacy screens arranged withmicro-louvers 23 at right angles to each other can provide privacy intwo orthogonal dimensions.

In one prior-art method described in U.S. Patent Application Publication20080144179, privacy screens are made by coating a layer ofphoto-sensitive resin on a first substrate. A mask is used to patternthe photo-sensitive resin. The mask has a pattern corresponding to thearrangement of light-absorbing material 84 and transparent material 86.The pattern is etched into the exposed resin and a layer of curablematerial is coated over the photo-lithographically etched resin in avacuum. The curable material is etched to expose the photo-sensitiveresin layer, and cured. A transparent second substrate is then laminatedto the resin layer. Alternatively, the second substrate is laminatedafter the resin is etched and curable material wicked into the etchedareas using capillary forces, and cured. In yet another method, multipleresin layers having etched areas are laminated together forming gaps andcurable material wicked into the gaps using capillary forces, and cured.These methods are limited in the depth they can achieve sincephoto-lithographic etching has a practical depth limitation or thepatterns available are limited to those that can support etching.Furthermore, photo-lithographic processes are relatively expensive andslow.

In other prior-art methods described in U.S. Pat. No. 3,524,789,alternating layers of light-absorbing material 84 and light-transparentmaterial 86 are laminated together, for example as shown in thecross-section A of FIG. 16. Such layers can be formed by extrusion or bylaminating pre-formed sheets together, as is also described in EuropeanPatent Application No. 466,460. The laminate is then cut intocross-sectional portions, each portion forming the micro-louver sheet 12with micro-louvers 23 of width W separated by a separation distance S.Alternatively, as illustrated in the perspective of FIG. 17, alternatinglayers of light-absorbing material 84 and light-transparent material 86are formed in cylinders and laminated together. Thin micro-louver sheets12 (not shown) are cut from the cylinder with a knife 70.

These approaches use relatively thick layers of light-absorbing material84 and light-transparent material 86 that limit the transparency of theresulting micro-louver sheet 12. It is also difficult to make largemicro-louver sheets 12 since it is difficult to cut large, thin sheets,for example using skiving. Furthermore, such sheets typically needadditional processing to remove curl and polish the edges.

Attributes such as transparency, contrast, or reflectivity are importantfor optical systems. Overall thickness and cost are also importantdevice attributes.

SUMMARY OF THE INVENTION

There is a need therefore for micro-louver structures and manufacturingmethods providing improved transparency and reduced viewing angle,weight, thickness, and cost.

In accordance with the present invention, a micro-louver structurecomprises:

-   -   a cured layer on a surface;    -   a plurality of micro-channels in the cured layer, wherein the        micro-channels have a greater depth than width and are spaced        apart by a separation distance greater than the width; and    -   a cured light-absorbing material in the micro-channels.

Structures and methods of the present invention provide improvedtransparency and reduced viewing angle, weight, thickness, and cost formicro-louver sheets. Improved transparency is provided by enablingreduced micro-louver thickness and fewer layers. Reduced viewing angleis provided by reduced micro-louver thickness, increased micro-louverdepth, and multiple micro-louver layers. Reduced weight is provided byreducing the number and thickness of the various layers; reduced cost isachieved through a roll-to-roll manufacturing process that avoidspatterned photo-lithographic exposure and etching steps and avoidsskiving. Micro-louver sheets of the present invention are useful asprivacy screens for display systems in one or two dimensions. In such anapplication, reduced reflectivity or improved contrast of themicro-louver sheets is desirable, as well as inhibited or restricteddisplay viewing angle.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become more apparent when taken in conjunction with the followingdescription and drawings wherein identical reference numerals have beenused to designate identical features that are common to the figures, andwherein:

FIG. 1 is a cross-sectional view of a micro-louver structure in anembodiment of the present invention;

FIGS. 2A and 2B are cross-sectional views of micro-louver structures inother embodiments of the present invention;

FIGS. 3-6 are plan views of micro-louver structures in variousembodiments of the present invention;

FIG. 7 is a perspective of a micro-louver structure corresponding toFIG. 4 according to an embodiment of the present invention;

FIG. 8 is a cross-sectional view of a micro-louver structure and displayin another embodiment of the present invention;

FIGS. 9-11 are cross-sectional views of layered micro-louver structureswith different separations and spatial phases in other embodiments ofthe present invention;

FIGS. 12-14 are flow diagrams illustrating various methods of thepresent invention;

FIG. 15 is an exploded perspective of a prior-art micro-louver sheet;

FIG. 16 is a cross-sectional view of a prior-art micro-louver structureuseful in understanding the manufacture of micro-louver sheetscorresponding to FIG. 15; and

FIG. 17 is a perspective of a prior-art micro-louver structure useful inunderstanding the manufacture of micro-louver sheets.

The Figures are not necessarily to scale, since the range of dimensionsin the drawings is too great to permit depiction to scale.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to micro-louvers formed in sheets. Inan embodiment of the present invention illustrated in FIG. 1, amicro-louver structure 5 includes a cured layer 20 on a surface 15, forexample the surface 15 of a substrate 10. The cured layer 20 has aplurality of imprinted micro-channels 22 forming a pattern in the curedlayer 20. The imprinted micro-channels 22 have a greater depth D than awidth W and are spaced apart by a separation distance S greater than thewidth W of the imprinted micro-channel 22. A cured light-absorbingmaterial 24 is located in the imprinted micro-channels 22. The curedlight-absorbing material 24 in the imprinted micro-channels 22 formmicro-louvers 23 in the micro-louver sheet 12 including the cured layer20.

In an embodiment, the cured layer 20 is formed on the surface 15 of thesubstrate 10. In another embodiment, the imprinted micro-channels 22 andthe cured light-absorbing material 24 extend only partially through thecured layer 20 from a surface 11 of the cured layer 20. The surface 11of the cured layer 20 is also a micro-louver sheet surface 11. The curedlayer 20 is substantially transparent, having a transparency greaterthan or equal to 50%, 70, 80%, 90%, or 95%.

Referring to the cross-sectional view of FIG. 2A, the micro-louverstructure 5 includes a protective layer 30 on the cured layer 20 and incontact with the cured light-absorbing material 24 in the imprintedmicro-channels 22. In an embodiment, the protective layer 30 is itself acured layer or includes the same material as the cured layer 20. Inalternative embodiments, the protective layer 30 is laminated as a sheetto the micro-louver sheet 12 or is coated as an uncured layer and thencured, for example with radiation. In an embodiment, anti-reflectivelayers 32 are located on the protective layer 30 opposite the curedlayer 20. Referring to FIG. 2B in another embodiment, other layers, forexample the anti-reflective layers 32, are located between theprotective layer 30 and the cured layer 20 in the micro-louver structure5 so that the protective layer 30 is not in contact with thelight-absorbing material 24. The anti-reflective layers 32 serve toreduce reflections from the surface of the cured layer 20 (FIG. 2B) orprotective layer 30 (FIG. 2A).

In an embodiment, an uncured curable layer 20 is coated over thesubstrate 10 and cured to form cured layer 20. The curable layer 20 caninclude cross-linking materials that are cured, for example withradiation, to form the cured layer 20. Similarly, uncured curablelight-absorbing material 24 is coated over the substrate 10 and cured toform the cured light-absorbing material 24 in the imprintedmicro-channels 22. The curable light-absorbing materials 24 can includecross-linking materials that are cured, for example with radiation, toform the cured light-absorbing material 24 and the micro-louvers 23.

As used herein, a cured layer or material is cured in situ after it hasbeen placed in its final location. For example, the curable layer 20 iscoated on substrate 10 and then cured. The curable layer 20 is not firstcured and then subsequently located on substrate 10. Similarly, thecurable light-absorbing material 24 is first located in the imprintedmicro-channels 22, for example by coating, and then cured. The curablelight-absorbing material 24 is not first cured and then subsequentlylocated in the imprinted micro-channels 22. Such a curing method enablesefficient and effective construction of the elements of the presentinvention. An example of a suitable material for a curable layer is SU8,a well-known material in the photo-lithographic arts. In the Figures,the imprinted micro-channels 22 are indicated with an arrow while thecured light-absorbing material 24 in the imprinted micro-channels 22 isindicated with a lead line. The light-absorbing material 24 in theimprinted micro-channels 22 form the micro-louvers 23. Furthermore, thelayer 20 is referred to as both a curable layer 20 and a cured layer 20,depending on whether the material making up the layer 20 has been curedor not. Similarly, the light-absorbing material 24 is referred to asboth a curable light-absorbing material 24 and a cured light-absorbingmaterial 24, depending on whether the light-absorbing material 24 hasbeen cured or not.

The substrates 10, for example made of glass or plastic, curable layers20, for example including curable resins, and curable light-absorbingmaterials, for example including carbon black in a curable resin, areknown in the art as are methods for their preparation, deposition, andcuring.

In a further embodiment of the present invention, the curedlight-absorbing material 24 is cross-linked to the cured layer 20. Insuch an embodiment, both the curable light-absorbing material 24 and thecurable layer 20 can include cross-linkable materials that cross linkwhen cured. For example, both the curable light-absorbing material 24and the curable layer 20 can include a common curable resin, for examplecured with ultra-violet radiation or heat, that cross links when cured.Such cross-linking between the cured light-absorbing material 24 and thecured layer 20 improves the strength of the micro-louver sheet 12 andimproves the scratch resistance of the micro-louvers 23.

In an embodiment of the present invention, the depth D of the imprintedmicro-channels 22 (and micro-louvers 23) is at least two times, fourtimes, ten times, fifteen times, twenty times, thirty times, or fiftytimes greater than the width W. As the depth D of the micro-louvers 23increases and the width W decreases, the viewing angle of themicro-louver structure 5 decreases and the transparency of themicro-louver structure 5 increases. Therefore, in an embodiment of thepresent invention, the width W of the imprinted micro-channels 22 isless than or equal to four microns, two microns, or one micron.

In an embodiment, a cross-section of the imprinted micro-channels 22 ina plane parallel to the micro-louver sheet surface 11 of the cured layer20 substantially forms an array of lines in one direction. Referring toFIG. 3, the micro-louver structure 5 includes the cured layer 20 havingcured light-absorbing material 24 in lines of imprinted micro-channels22 forming micro-louvers 23. In this embodiment, a privacy screen willlimit a user's view in a direction orthogonal to the line direction.

In an alternative embodiment, a cross-section of the imprintedmicro-channels 22 in a plane parallel to the micro-louver sheet surface11 of the cured layer 20 substantially forms rows and columns of linesextending in two different directions forming a grid. Referring to FIG.4 in a cross-sectional view and to FIG. 7 in perspective, themicro-louver structure 5 includes the cured layer 20 having curedlight-absorbing material 24 in lines of imprinted micro-channels 22forming micro-louvers 23 in two dimensions. Micro-louvers 23A extend inone dimension and micro-louvers 23B extend in an orthogonal dimension.In this embodiment, a privacy screen will limit a user's view in both oftwo orthogonal directions. Such a structure cannot be made with theprior-art methods illustrated in FIGS. 16 and 17.

According to various embodiments of the present invention, themicro-louvers 23 need not form straight lines (when viewed in plan view)or portions of a plane (when viewed from the side). For example,referring to FIG. 5, the micro-louver structure 5 includes the curedlayer 20 having cured light-absorbing material 24 in circular imprintedmicro-channels 22 forming circular micro-louvers 23. Alternatively,referring to FIG. 6, the micro-louver structure 5 includes the curedlayer 20 having cured light-absorbing material 24 in octagonal imprintedmicro-channels 22 forming octagonal micro-louvers 23. Thus,micro-louvers 23 can form circles, polygons, or other regular orirregular shapes. In some embodiments, the shapes form simple closedcurves, in others the shapes are curves, lines, line segments, areinterconnected or are separate.

Referring to FIG. 8 in yet another embodiment of the present invention,the micro-louver structure 5 of the present invention is incorporated asa component into a system including the display 40 with a displaysubstrate 44 and the display cover 42. The cured layer 20 is formed on,or laminated to, the display cover 42. In this embodiment, the substrate10 of FIG. 1 is a component of the display 40 and corresponds to thedisplay cover 42. The display 40 can be, for example, a liquid crystaldisplay or top-emitting organic light-emitting diode (OLED) display. Inan alternative embodiment (not shown), the substrate 10 is the displaysubstrate 44, for example in a bottom-emitting OLED display. Othermaterials or structures are formed in the display 40 between the displaycover 42 and the display substrate 44 but are not illustrated, forexample electrode layers, backlights, liquid crystal layers, or organicmaterial layers.

As illustrated in FIG. 8, the orthogonal emitted light 54 emittedorthogonally from the display 40 passes through the micro-louverstructure 5. The light 50 emitted at a small angle to the display 40orthogonal also passes through the micro-louver structure 5. However,the blocked light 52 emitted at a large angle to the display 40orthogonal is absorbed by the light-absorbing material 24 of themicro-louver structure 5. Thus, the micro-louver structure 5 forms aprivacy screen for the display 40.

In another embodiment of the present invention, two cured layers 20 arelocated together in a spatial relationship. As illustrated in FIGS. 9and 10, the micro-louver structure 5 includes a first cured layer 20Awith micro-louvers 23A. The first cured layer 20A is formed on thesurface 15 of the substrate 10. A second cured layer 20B withmicro-louvers 23B is formed on the substrate first cured layer 20A. Asillustrated in FIG. 9, the micro-louvers 23A in the first cured layer20A are spatially in phase with the micro-louvers 23B in the secondcured layer 20B. As illustrated in FIG. 10, the micro-louvers 23A in thefirst cured layer 20A are spatially out of phase with the micro-louvers23B in the second cured layer 20B by 180 degrees.

Referring to FIG. 11, the substrate 10 of the micro-louver structure 5has the substrate surface 15 and an opposed substrate surface 13. Inthis embodiment, the two cured layers 20A, 20B and the micro-louvers23A, 23B are located on the opposing surfaces 13, 15 of the substrate10. As illustrated, the micro-louvers 23A, 23B are spatially in phase,but in an alternative embodiment (not shown), the micro-louvers 23A, 23Bare spatially out of phase, for example but not necessarily 180 degreesout of phase.

By locating the micro-louvers 23A and the micro-louvers 23B in a spatialrelationship, the effective optical depth of the micro-louvers 23A, 23Bis increased, thus reducing further the viewing angle of themicro-louver structure 5. Whether multiple cured layers 20 or in-phaseor out-of-phase micro-louvers is desired depends at least in part on theseparation distance S, depth D, or width W of the micro-louvers (asshown in FIG. 1), and the desired viewing angle characteristics.

The substrate 10 of FIGS. 9-11 can be a component of the display 40, forexample the display cover 42 or the display substrate 44.

A micro-louver structure 5 of the present invention is used by locatingthe micro-louver structure 5 in an optical system in which it is desiredto inhibit transmission through the optical system at large angles tothe optical axis. The micro-louver structure 5 can also be used bylocating the micro-louver structure 5 over the display 40 and viewingthe display 40 and micro-louver structure 5 at an orthogonal to thedisplay 40 and not viewing the display 40 and micro-louver structure 5at angles that are large with respect to an orthogonal to the display40.

Referring to FIG. 12, a method of the present invention includes makingthe micro-louver structure 5 that includes providing the substratesurface 15 in step 100. The curable layer 20 is provided in step 105 onthe substrate surface 15, for example by coating. A wide variety ofcoating techniques are available and known in the art, for example spraycoating, curtain coating, hopper coating, slot coating, or transfercoating. The curable layer 20 can include a photo-curable orheat-curable resin. Such resins are known in the art.

In step 110, the pattern of micro-channels 22 is imprinted in thecurable layer 20. The imprinted micro-channels 22 have a greater depth Dthan width W and are spaced apart by a separation distance S greaterthan the width W. The imprinted micro-channels 22 are imprinted using astamp located in the curable layer 20 and the curable layer 20 is atleast partially cured in step 115 to form the cured layer 20. The stamphas a relief pattern that is the inverse of the micro-channel pattern.Imprinted micro-channels 22 having a depth D more than two to six timesthat of width W for various widths W, for example between 1 and 5microns, have been demonstrated. Methods for making stamps, locatingthem in the coated curable layer 20, and curing the curable layer 20 toform the cured layer 20 with micro-channels 22 imprinted therein areknown in the art.

In step 120, the stamp is removed leaving the cured layer 20 withimprinted micro-channels 22. A curable light-absorbing material 24 iscoated over the cured layer 20 and in the imprinted micro-channels 22 instep 125. At least a portion of the light-absorbing material 24 isremoved in step 130 from the micro-louver sheet surface 11 of the curedlayer 20 and at least a portion of the light-absorbing material 24 isleft in the imprinted micro-channels 22. In step 135, thelight-absorbing material 24 is cured to form a light-absorbingmicro-louver structure 5 in each micro-channel 22.

In a further embodiment of the present invention, the cured layer 20 isoptionally polished or an optional protective layer 30 is formed in step140. Alternatively, the cured layer 20 is removed from the substratesurface 15 (step 145) and laminated to another surface (step 150). Forexample, the cured layer 20 is laminated to the display cover 42 ordisplay substrate 44.

As shown in FIG. 12, the steps 125, 130, and 135 of coating the curedlayer 20 and the imprinted micro-channels 22 with the curablelight-absorbing material 24, removing the excess curable light-absorbingmaterial 24 from the cured-layer surface 11, and curing thelight-absorbing material 24 are repeated as necessary to fill theimprinted micro-channels 22 with cured light-absorbing material 24.

In another embodiment, multiple layers 20 of cured material areiteratively coated over the cured layer 20 (step 105), imprinted (step110), cured (step 115), the imprinting stamp removed (step 120), thecured layer 20 coated with light-absorbing material 24 (step 125),excess light-absorbing material 24 removed (step 130) and cured (step135) to create micro-louver structures 5 such as those illustrated inFIGS. 9 and 10. As illustrated in FIG. 13, multiple layers 20 of curedmaterial are provided. In step 100, the substrate surface 15 isprovided. The first cured layer 20A is formed on the substrate surface15 in step 200 (including steps 105-135 of FIG. 12). The second curedlayer 20B is formed in step 205 (including the same steps as for thefirst cured layer 20A) on the first micro-louver sheet surface 11.

Alternatively, a micro-louver structure 5 is formed on either side ofthe substrate 10. As illustrated in FIG. 14, a substrate 10 having twoopposing substrate surfaces 13, 15 is provided in step 101. The firstcured layer 20A is formed on the substrate surface 13 in step 201(including steps 105-135 of FIG. 12). The second cured layer 20B isformed on the opposing substrate surface 15 in step 250 (including thesame steps as for the first cured layer 20A).

In various embodiments, the curable layer 20 or the light-absorbingmaterial 24 is provided including cross-linking materials. The curablelayer 20 or the light-absorbing material 24 is cured withelectromagnetic radiation or heat. In one embodiment, the step of curingthe light-absorbing material 24 also at least partially cures thecurable layer 20 so that the curable layer 20 is cross linked to thelight-absorbing material 24.

In other embodiments, methods of the present invention include formingthe depth of the imprinted micro-channels 22 to be at least two timesgreater than the width of the imprinted micro-channels 22, four timesgreater than the width, five times greater than the width, eight timesgreater than the width, or ten times greater than the width. In anotherembodiment, a method of the present invention includes forming the widthof the imprinted micro-channels 22 to be less than or equal to fourmicrons, two microns, or one micron.

In another embodiment of the present invention, a method includesforming imprinted micro-channels 22 so that a cross-section of theimprinted micro-channels 22 in a plane parallel to the surface of thecured layer 20 substantially forms an array of lines in one direction(as illustrated in FIG. 3). Alternatively, a method includes formingimprinted micro-channels 22 so that a cross-section of the imprintedmicro-channels 22 in a plane parallel to the surface of the cured layer20 substantially forms a grid in one direction (as illustrated in FIG.4). In other embodiments, methods of the present invention includeforming imprinted micro-channels 22 so that a cross-section of theimprinted micro-channels in a plane parallel to the surface of the curedlayer 20 substantially forms one or more polygons (as shown in FIG. 6)or one or more circles (as shown in FIG. 5).

In another embodiment of the present invention, the imprintedmicro-channels 22 are formed to extend only partially through thecurable layer 20, as illustrated in FIG. 1.

Another method of the present invention included laminating two or moremicro-louver structures 5 together or forming two micro-louverstructures 5 and laminating the two micro-louver structures 5 together(as shown in FIG. 9). The step of laminating can further includelaminating the two micro-louver structures 5 together spatially in phaseor spatially 180 degrees out of phase (as shown in FIGS. 9 and 10).Alternatively, a method of the present invention can further includeproviding the substrate 10 and forming two micro-louver structures 5 onopposing substrate surfaces 13, 15 of the substrate 10. The micro-louverstructures 5 can be formed spatially in phase or spatially 180 degreesout of phase.

A method of making a micro-louver structure 5 for use with the display40 that permits orthogonal display viewing while inhibiting displayviewing at larger angles to the orthogonal includes forming themicro-louver structure 5 by coating the curable layer 20 on a surface,for example a substrate surface 15 and imprinting a pattern ofmicro-channels 22 in the curable layer 20. The imprinted micro-channels22 have a greater depth D than width W and are spaced apart by aseparation distance S greater than the width W. The curable layer 20 isat least partially cured to form a cured layer 20 that is coated with alight-absorbing material 24 in the imprinted micro-channels 22. At leasta portion of the light-absorbing material 24 is removed from themicro-louver sheet surface 11 of the cured layer 20 leaving at least aportion of the light-absorbing material 24 in the imprintedmicro-channels 22. The light-absorbing material 24 is cured to form alight-absorbing structure forming a micro-louver 23 in each imprintedmicro-channel 22. The micro-louver structure 5 is located on a viewingsurface of the display 40, whereby orthogonal display viewing is enabledwhile display viewing at larger angles is inhibited. Alternatively, themicro-louver structure 5 is formed on a substrate 10 that is an elementof the display 40, for example the display cover 42 or display substrate44.

According to various embodiments of the present invention, a substrate10 is any material having the substrate surface 15 on which the curablelayer 20 can be formed. For example, glass and plastic are suitablematerials known in the art from which the substrates 10 can be made intosheets of material having substantially parallel opposed sides, one ofwhich is the substrate surface 15. In various embodiments, substrate 10is rigid, flexible, or transparent.

The substrate 10 can have a wide variety of thicknesses, for example 10microns, 50 microns, 100 microns, 1 mm, or more. In various embodimentsof the present invention, the substrate 10 is provided as an element ofother devices, for example the display cover 42 or display substrate 44of the display 40 or the curable layer 20 is coated on anotherunderlying substrate 10, for example by coating the curable polymerlayer on an underlying glass substrate 10, such as the display cover 42.Alternatively, the substrate 10 can be affixed to the display 40 orother device.

An imprinted micro-channel 22 is a groove, trench, or channel formed inthe curable layer 20 and extending from the cured-layer surface 11toward substrate 10 and having a cross-sectional width W, for exampleless than or equal to 20 microns, 10 microns, 5 microns, 4 microns, 3microns, 2 microns, 1 micron, or 0.5 microns. In an embodiment, thecross-sectional depth D of the imprinted micro-channel 22 is greaterthan or equal to twice the width W, five times the width W, ten timesthe width W, fifteen times the width W, twenty times the width W, thirtytimes the width W, or fifty times the width W. The micro-channels 22 canhave a rectangular cross-section, as shown. Other cross-sectionalshapes, for example trapezoids, are known and are included in thepresent invention.

Material compositions useful in the curable layer 20 or the curablelight-absorbing material 24 can be provided in one state and thenprocessed into another state, for example converted from a liquid stateinto a solid state. Such conversion can be accomplished in a variety ofways, for example by drying or heating. Furthermore, useful materialcompositions can include a set of materials that, after deposition andprocessing, is reduced to a subset of the set of materials, for exampleby removing solvents from the material composition. For example, amaterial composition including a solvent is deposited and then processedto remove the solvent leaving a material composition without the solventin place. Thus, according to embodiments of the present invention, amaterial composition that is deposited on the substrate 10 or in theimprinted micro-channels 22 is not necessarily the same composition asthat found in the cured material composition.

In one embodiment, the light-absorbing material 24 includes carbonblack, a black dye, or a black pigment. In another embodiment, thelight-absorbing material 24 includes a colored dye or a colored pigmentother than black. U.S. Patent Application Publication No. 2008/0257211discloses a variety of metallic colored inks and its contents are herebyincorporated by reference. In a further embodiment, the substrate 10 andthe cured layer 20 are substantially transparent.

Curing material compositions such as those in the curable layer 20 or inthe curable light-absorbing material 24 can be done by drying or heatingin stages. In particular, if the curable layer 20 is a polymer layer,heating the polymer layer slightly can soften the polymer so thatparticles, for example black pigment or carbon black particles in thelight-absorbing material 24 can adhere to the polymer. Such heating canbe done by convective heating (putting substrate 10 into an oven) or byinfrared radiation. Heating with infrared radiation has the advantagethat light-absorbing particles, for example black particles,differentially absorb the infrared radiation and heat up more thansubstrate 40 or curable layer 20 (that can be transparent), thusproviding a more efficient adhesion or drying process for a materialcomposition. Adhesion of the curable layer 20 to the light-absorbingmaterial 24 is advantageous because such adhered materials are moreresistant to mechanical abrasion and are thus more environmentallyrobust.

Methods and device for forming and providing substrates, coatingsubstrates, patterning coated substrates, or pattern-wise depositingmaterials on a substrate are known in the photo-lithographic arts.Likewise, tools for laying out electrodes, conductive traces, andconnectors are known in the electronics industry as are methods formanufacturing such electronic system elements. Hardware controllers forcontrolling touch screens and displays and software for managing displayand touch screen systems are all well known. All of these tools andmethods can be usefully employed to design, implement, construct, andoperate the present invention. Methods, tools, and devices for operatingcapacitive touch screens can be used with the present invention.

The present invention is useful in a wide variety of electronic devices.Such devices can include, for example, photovoltaic devices, OLEDdisplays and lighting, LCD displays, plasma displays, inorganic LEDdisplays and lighting, electrophoretic displays, electrowettingdisplays, dimming mirrors, smart windows, transparent radio antennae,transparent heaters and other touch screen devices such as resistivetouch screen devices.

The invention has been described in detail with particular reference tocertain embodiments thereof, but it will be understood that variationsand modifications can be effected within the spirit and scope of theinvention.

PARTS LIST

A cross-section

D depth

L length

S separation distance

W width

X x dimension

Y y dimension

Z z dimension

5 micro-louver structure

10 substrate

11 surface

12 micro-louver sheet

13 opposed substrate surface

15 substrate surface

20 curable/cured layer

20A first curable/cured layer

20B second curable/cured layer

22 imprinted micro-channel

23 micro-louver

23A micro-louver

23B micro-louver

24 light-absorbing material

26 transparent material

28 extensive surface

30 protective layer

32 anti-reflective layer

40 display

42 display cover

44 display substrate

Parts List Cont'd

50 light

52 blocked light

54 orthogonal emitted light

70 knife

84 light-absorbing material

86 transparent material

100 provide surface step

101 provide substrate step

105 provide curable layer step

110 imprint micro-channels in curable layer with stamp step

115 cure curable layer and micro-channels step

120 remove stamp step

125 coat cured layer and micro-channels with light-absorbing materialstep

130 remove light-absorbing material cured-layer surface step

135 cure light-absorbing material step

140 optional form protective layer step

145 remove cured layer from surface step

150 laminate cured surface to display step

200 form first cured layer on surface step

201 form first cured layer on substrate surface step

205 form second cured layer on first cured layer step

250 form second cured layer on opposing surface of substrate step

1. A micro-louver structure, comprising: a cured layer on a surface; aplurality of imprinted micro-channels in the cured layer, wherein theimprinted micro-channels have a greater depth than width and are spacedapart by a separation distance greater than the width; and a curedlight-absorbing material in the micro-channels.
 2. The micro-louverstructure of claim 1, wherein the imprinted micro-channels extend onlypartially through the cured layer.
 3. The micro-louver structure ofclaim 1, further including a protective layer on the cured layer and incontact with the cured light-absorbing material.
 4. The micro-louverstructure of claim 1, further including a protective layer on the curedlayer but not in contact with the cured light-absorbing material.
 5. Themicro-louver structure of claim 1, wherein the cured layer or thelight-absorbing material includes cross-linking materials.
 6. Themicro-louver structure of claim 1, wherein the light-absorbing materialis cross-linked to the cured layer.
 7. The micro-louver structure ofclaim 1, wherein the light-absorbing material includes carbon black. 8.The micro-louver structure of claim 1, wherein the depth of theimprinted micro-channels is at least two times greater than the width,four times greater than the width, five times greater than the width,eight times greater than the width, or ten times greater than the width.9. The micro-louver structure of claim 1, wherein the width of theimprinted micro-channels is less than or equal to four microns, twomicrons, or one micron.
 10. The micro-louver structure of claim 1,wherein a cross-section of the imprinted micro-channels in a planeparallel to the surface of the cured layer substantially forms an arrayof lines in one direction.
 11. The micro-louver structure of claim 1,wherein a cross-section of the imprinted micro-channels in a planeparallel to the surface of the cured layer substantially forms a gridwith lines extending in two different directions.
 12. The micro-louverstructure of claim 1, wherein a cross-section of the imprintedmicro-channels in a plane parallel to the surface of the cured layersubstantially forms one or more polygons or circles.
 13. Themicro-louver structure of claim 1, further including a substrate havingthe surface and wherein the substrate is a component of a display. 14.The micro-louver structure of claim 13, wherein the substrate is adisplay cover or display substrate.
 15. The micro-louver structure ofclaim 1, further including two cured layers located together in aspatial relationship.
 16. The micro-louver structure of claim 15,wherein the micro-channels of the two cured layers are spatially inphase or spatially 180 degrees out of phase.
 17. The micro-louverstructure of claim 15, further including a substrate having opposedsurfaces and wherein the two cured layers are located on opposingsurfaces of the substrate.
 18. The micro-louver structure of claim 15,further including a substrate having a surface and wherein a first oneof the cured layers is located on the surface of the substrate and asecond one of the cured layers is located on the first one of the curedlayers.
 19. The micro-louver structure of claim 15, further including asubstrate having the surface on which at least one of the cured layersis formed and wherein the substrate is a component of a display.
 20. Amicro-structure for use with a display which permits orthogonal displayviewing while inhibiting display viewing at larger angles, comprising: acured layer on a surface; a plurality of imprinted micro-channelsforming a pattern in the cured layer, wherein the imprintedmicro-channels have a greater depth than width and are spaced apart by aseparation distance greater than the width; a cured light-absorbingmaterial in the imprinted micro-channels; and wherein themicro-structure is located on a viewing surface of the display, wherebyorthogonal display viewing is enabled while display viewing at largerangles is inhibited.